Living together in a single mother household, a mother is approached one day by her son seeking advice. While soaking together in the bathtub, she listens to her son's troubles. He's been mocked by friends, told he's the only one who's never been with a woman. Feeling a sense of parental responsibility, the mother decides to teach her son firsthand what a woman's body is like, using her own. Their relationship gradually escalates, until they ultimately cross the line and become lovers. Unable to forget her son's mature body, the mother later masturbates while fantasizing about him. Eventually, unable to restrain herself any longer, she gives in and sleeps with her son again... What will become of them in the end?